The field of the invention is extruded plastics, particularly as used in telecommunications cables.
Polyvinyl chlorides (PVC) containing plasticizers are well known in making tubes for telecommunications cables. However, the plasticizers have a tendency to migrate into adjacent oils or greases present in the environment or in the cables themselves performing waterblocking functions. Such migration leaves the PVC in a brittle condition. The plasticized PVC also has a limited temperature range and is subject to fungal attack, leading to proposals to add antifungal agents to the plastic blends.
Polyurethanes (PUR), also well known materials for use in telecommunications cables, have a high tackiness which leads to handling problems, mainly during respooling or the take-up process, leading to light waveguide microbending.
Garaflex GF 50-10B is a commercially available blend of PVC and ester-based PUR suitable in some applications, but still having poor fungal resistance and poor hydrolytic stability, rendering the material unsuitable for use in applications exposed to the outdoor environment.